[hibernate-dev] replace Pax Exam with Docker

[Brett Meyer]

Sorry Gunnar/Sanne, should have clarified this first:

We actually used Arquillian before Pax Exam, and the experience was far 
worse (somewhat of a long story)...

 > Pax Exam was just "helping" to deploy/run things in Karaf, so I can't 
imagine using Karaf without the helpers being a walk in the park

That's not actually the case.  The way Pax Exam currently runs our tests 
is fundamentally part of the problem.  The test code is dynamically 
wrapped in an actual bundle, using something like tiny-bundles, and 
executed *within* the container itself. Pax overrides runs with 
additional probes, overrides logging infrastructure, etc.  Those nuances 
can often be the source of many of the bugs (there are a ton of 
classloader implications, etc. -- IIRC, this was one area where 
Arquillian was much, much worse).  There are some benefits to that 
setup, but for Hibernate it mainly gets in the way.

It *does* have a "server mode" where tests run outside of the container, 
but I vaguely remember going down that path early on and hitting a 
roadblock.  For the life of me, I can't remember the specifics.  But my 
pushback here is that ultimately Docker might be more preferable, giving 
us more of a real world scenario to do true e2e tests without something 
else in the middle.

 > so I can't imagine using Karaf without the helpers being a walk in 
the park; e.g. having to deal with HTTP operations comes with its own 
baggage {dependencies, complexity, speed, .. } and generally more stuff 
to maintain.

I guess I respectfully disagree with that, but purely due to Karaf 
features.  Our features.xml does most of the heavy lifting for us w/r/t 
getting Hibernate provisioned.  The same would be true with the test 
harness bundle/feature.  REST is simple and out-of-the-box thanks to 
Karaf + CXF or Camel.  For other possible routes (Karaf commands), we 
already have code available in our demo/quickstart projects.

 > Also: considered contributing to Pax?

Yes, of course.  But the fact that numerous Karaf *committers* 
themselves have a long history of built-up frustration on it doesn't 
leave me optimistic.  A couple of them had tried to pitch in at one 
point and weren't able to get anywhere.

 > but it seems their developers really expect their users to be deeply 
familiar with it all

Absolutely!  But again, our struggles also come down to the fundamental 
way Pax Exam works...


On 1/12/18 6:27 AM, Sanne Grinovero wrote:
> +1 to explore alternatives to Pax Exam, but I'd be wary of maintining
> our own test infrastructure.
>
> Pax Exam was just "helping" to deploy/run things in Karaf, so I can't
> imagine using Karaf without the helpers being a walk in the park; e.g.
> having to deal with HTTP operations comes with its own baggage
> {dependencies, complexity, speed, .. } and generally more stuff to
> maintain.
>
> So.. +1 to try out Arquillian or anything else. Or maybe you could
> start your own tool, but I'd prefer to see it in a separate repository
> :) e.g. a nice Gradle plugin so maybe you get more people helping?
>
> Also: considered contributing to Pax? My personal experience with it
> has always been a pain but if I had to try identify the reason, it was
> mostly caused by me being unfamiliar with Karaf and not having good
> clues to track down the real failure; maybe some minor error reporting
> improvements could make a big difference to its usability? Just
> saying, I don't feel like Pax is bad, but it seems their developers
> really expect their users to be deeply familiar with it all - feels
> like the typical case in which they could use some feedback and a
> hand.
>
> Thanks,
> Sanne
>
> On 12 January 2018 at 08:22, Gunnar Morling <gunnar at hibernate.org> wrote:
>> Hi Brett,
>>
>> We also had our fair share of frustration with Pax Exam in HV, and I was
>> (more than once) at the point of dropping it.
>>
>> Docker could work, but as you say it's a bit of a heavy dependency, if not
>> required anyways. Not sure whether I'd like to add this as a prerequisite
>> for the HV build to be executed. And tests in separate profiles tend to be
>> "forgotten" in my experience.
>>
>> One other approach could be to use Arquillian's OSGi support (see
>> https://github.com/arquillian/arquillian-container-osgi), did you consider
>> to use that one as an alternative?
>>
>> Cheers,
>>
>> --Gunnar
>>
>>
>> 2018-01-12 3:34 GMT+01:00 Brett Meyer <brett at hibernate.org>:
>>
>>> <tired-rant>
>>>
>>> I'm fed up with Pax Exam and would love to replace it as the
>>> hibernate-osgi integration test harness.  Most of the Karaf committers
>>> I've been working with hate it more than I do.  Every single time we
>>> upgrade the Karaf version, something less-than-minor in hibernate-osgi,
>>> upgrade/change dependencies, or attempt to upgrade Pax Exam itself,
>>> there's some new obfuscated failure.  And no matter how much I pray, it
>>> refuses to let us get to the container logs to figure out what
>>> happened.  Tis a house of cards.
>>>
>>> </tired-rant>
>>>
>>> One alternative that recently came up elsewhere: use Docker to bootstrap
>>> the container, hit it with our features.xml, install a test bundle that
>>> exposes functionality externally (over HTTP, Karaf commands, etc), then
>>> hit the endpoints and run assertions.
>>>
>>> Pros: true "integration test", plain vanilla Karaf, direct access to all
>>> logs, easier to eventually support and test other containers.
>>>
>>> Cons: Need Docker installed for local test runs, probably safer to
>>> isolate the integration test behind a disabled-by-default Maven profile.
>>>
>>> Any gut reactions?
>>>
>>> OSGi is fun and I'm not at all bitter,
>>>
>>> -Brett-
>>>
>>> ;)
>>>
>>>
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